For rechargeable batteries such as lithium (i.e., Li+) ion batteries, performance and battery life depend on structural and chemical stability of electrodes in the battery, minimizing the rate of degradation of electrolytes, and controlling formation of solid electrolyte interface (SEI) layers at or on the surface of the electrodes during repeated charge-discharge cycles. However, knowledge of the dynamic structural and chemical evolution of ionic and molecular species at the electrode-liquid electrolyte interface for a rechargeable battery remains limited due to an inability to directly probe the interface during operation under reaction conditions. Because electrode surfaces are normally enclosed in a liquid electrolyte, traditional analyses of electrode surfaces require disassembling the battery and examining the electrodes and their chemical composition using imaging and spectroscopic methods ex-situ. Unfortunately, post-operation examination does not provide real-time information about molecular and ionic species that form SEI layers, structural and chemical characteristics of SEI layers during formation, or the ability to correlate real-time data to the transport of ions of interest.
For example, solvation-desolvation reactions involving active ions in electrolytes have been mostly studied using electrospray ionization (ESI) and nuclear magnetic resonance (NMR) coupled with theoretical calculations. However, ESI and NMR are bulk analysis techniques that are not effective for studying solvation-desolvation processes occurring at the electrode-electrolyte interface. Hence, formation and evolution of SEI layers during the charge and discharge cycles of Li-ion conducting batteries, as well as the associated structures and chemical species associated with the SEI layers, and an ability to correlate data from these events to the transport of the Li+ ions remains elusive. A key shortcoming of observations related to formation of SEI layers is the lack of molecular information that is spatially adjacent to the electrolyte/electrode interface. Direct molecular level observation of structural and chemical evolution of electrode surface in a rechargeable battery has not previously been possible. Lack of data in these representative areas has limited advancements in performance of rechargeable Li-ion batteries to date. Accordingly, new devices and methods are needed that provide in-situ analyses of electrodes and evolution of SEI layers at the electrode and electrode-electrolyte interface during operation rather than relying on ex-situ analyses to advance performance of rechargeable batteries. The present disclosure addresses these needs.